Michael Woodford was axed after just two weeks in the top job after clashing with the board over allegedly excessive payments made to advisers during a 2008 acquisition.
He held meetings with the Serious Fraud Office in the UK yesterday, claiming a report carried out by PwC had raised concerns over the deal.
Now Olympus is threatening legal action against Woodford for leaking confidential information.
His departure was an acrimonious end to a 30-year career, in which he rose further than all but a handful of westerners in a country famed for its impenetrable corporate culture.
The ongoing saga has put a spotlight on what critics say is a key weakness of Japanese-style management, which often lacks strong independent oversight at board level.
Twelve of Olympus’ 15 board members are company executives, and one of its three outside directors failed to pass a test of independence set by top proxy voting firms.
Chairman Tsuyoshi Kikukawa, who initially stepped aside to create space for Woodford, has resumed the chief executive role, increasing pressure on the firm to create a structure in which his authority can be challenged.
TIME LINE | THE RISE AND FALL OF MICHAEL WOODFORD
Michael Woodford joins Olympus. Over the next three decades he becomes the archetypal company man, known for his robust, no-nonsense management style.
Woodford takes over as president of the company, becoming one of only a handful of non-Japanese to run a large Japanese corporation.
Woodford is promoted to chief executive as well as maintaining his role as chairman. His appointment is hailed as giving Olympus more executive autonomy.
Woodford reportedly asks longstanding chairman Tsuyoshi Kikukawa to resign over payments made to advisors during a $2bn acquisition in 2008, following an independent report by PwC.
14 October 2011
Woodford is axed after the board unanimously backs Kikukawa. The move sends shares in the firm plummeting. Olympus says Woodford was dismissed because of a clash of management styles.
17 October 2011
Olympus tanks even further, losing a quarter of its value. Woodford makes it clear he will not let the issue lie, handing documents to the Serious Fraud Office in the UK. Olympus maintains there is no evidence of wrongdoing.